Air filter for medicinal liquid injection and medicinal liquid injection apparatus including the same

ABSTRACT

An air filter device for medicinal liquid injection in which a medicinal liquid channel is formed includes: a housing having an air passage that diverges from the medicinal liquid channel and is connected to outside; a hydrophilic boundary filter disposed in the medicinal liquid channel and dividing the medicinal liquid channel into a first channel at an upstream side and a second channel at a downstream side; and a hydrophobic air-passing filter disposed at a boundary between the air passage and the first channel.

TECHNICAL FIELD

The present disclosure relates to an air filter for medicinal liquid injection configured to filter out air in a medicinal liquid, and a medicinal liquid injection apparatus including the same.

BACKGROUND ART

A medicinal liquid injection apparatus that injects a liquid-state medicinal liquid (e.g., an injection) into a patient to supply medicine to the patients is known. A medicinal liquid that is in a predetermined storage space is injected into the body of a patient through a channel (e.g., the internal space of a tube and a needle) connected to the patient by the medicinal liquid injection apparatus.

A device having a medicinal liquid transfer pipe forming a capillary channel to prevent a medicinal liquid from being injected all at once into the body of a patient such that the medicinal liquid is slowly injected for a predetermined time for medical purposes is known. Since a medicinal liquid flows through the medicine transfer pipe, the flow rate of the medicinal liquid flowing through the channel of the medicinal liquid injection apparatus is reduced.

When the storage space is filled with a medicinal liquid, air may flow inside together with the medicinal liquid and move through the passage. Further, substances dissolved in the medicinal liquid (e.g., dissolve oxygen or dissolved carbon dioxide) may change into air and move through the passage, depending on conditions such as pressure in the passage.

DISCLOSURE OF INVENTION Technical Problem

Air moving through a passage may have a critical adverse influence on a patient when it flows into the patient's body. Further, when air moving through a passage clogs a medicine transfer pipe, the medicine transfer pipe has difficulty in performing its normal function. Embodiments of the present disclosure solve the problems in the related art.

There is a problem in that even though air is filtered out by an air filter device, substances dissolved in a medicinal liquid may change into air at a downstream side of the air filter device. Embodiments of the present disclosure solve the problems in the related art.

Solution to Problem

An aspect of the present disclosure provides embodiments of an air filter device for medicinal liquid injection in which a medicinal liquid channel is formed. An air filter device according to a representative embodiment includes: a housing having an air passage that diverges from the medicinal liquid channel and is connected to outside; a hydrophilic boundary filter disposed in the medicinal liquid channel and dividing the medicinal liquid channel into a first channel at an upstream side and a second channel at a downstream side; and a hydrophobic air-passing filter disposed at a boundary between the air passage and the first channel.

In embodiments, a surface of the air-passing filter facing the first channel may extend along a side of the first channel.

In embodiments, the first channel may include a contact channel configured such that a medicinal liquid in the contact channel comes in contact with the air-passing filter. The contact channel may be formed such that a length of the contact channel in a first direction facing the air-passing filter is shorter than a length of the contact channel in a second direction that is any one direction perpendicular to the first direction.

In embodiments, the air-passing filter may be configured to pass air in the first direction and extends in the second direction.

In embodiments, the contact channel may be formed such that a length of the contact channel in a third direction perpendicular to the first direction and the second direction is larger than a length of the contact channel in the first direction.

In embodiments, the air-passing filter may be configured to pass air in the first direction and extend in the second direction and the third direction.

In embodiments, a downstream side portion of the contact channel may be spaced apart from an upstream side portion of the contact channel in the second direction. The contact channel may be formed such that the length of the contact channel in the second direction is larger than the length of the contact channel in the third direction.

In embodiments, the first channel may include a contact channel configured such that a medicinal liquid in the contact channel comes in contact with the air-passing filter. A cross-section of the contact channel may be formed such that a length of the cross-section in a first direction facing the air-passing filter is shorter than a length of the cross-section in a second direction perpendicular to the first direction.

In embodiments, the first channel may include: a contact channel configured such that a medicinal liquid in the contact channel comes in contact with the air-passing filter; and a facing channel connected to an upstream side of the contact channel and configured to discharge the medicinal liquid into the contact channel in a first direction facing the air-passing filter.

In embodiments, the housing may include a facing protrusion protruding in the first direction to face the air-passing filter and having an outlet of the facing channel formed at a protrusive end of the facing protrusion.

In embodiments, the facing channel may extend in the first direction.

In embodiments, the housing may include an air-passing filter seat extending along an edge of the air-passing filter and coupled to the air-passing filter.

In embodiments, a gap may be formed between one side of the air-passing filter that is opposite to the other side of the air-passing filter facing the first channel, and an inner surface of the housing. The gap may constitute a portion of the air passage.

In embodiments, the air filter device may further comprise an additional hydrophobic air-passing filter disposed in the air passage and configured to pass air that has passed through the air-passing filter.

In embodiments, the housing may include an additional air-passing filter seat having a groove in which the additional hydrophobic air-passing filter is inserted.

In embodiments, the housing may include: a filter body in which the boundary filter is disposed; and a vent cap having a vent hole constituting at least a portion of the air passage, and coupled to the filter body.

In embodiments, the housing may include a gap-maintaining portion protruding in a direction facing the boundary filter to maintain a gap formed between one side of the boundary filter, the one side being opposite to the other side of the boundary filter facing the first channel, and an inner surface of the housing. The gap may constitute a portion of the second channel.

In embodiments, the second channel may include an extension channel connected to a downstream side of the gap and having a curved or bent portion.

In embodiments, the housing may have at least one vent hole positioned at a position where the air passage is connected to an external space. The at least one vent hole may include a plurality of vent holes arranged along a specified direction, or be elongated along the specified direction.

Another aspect of the present disclosure provides embodiments of a medicinal liquid injection apparatus. A medicinal liquid injection apparatus according to a representative embodiment includes: a pumping device configured to press a medicinal liquid; an extension tube in which the medicinal liquid flowing out of the pumping device by pressure applied by the pumping device flows; and an air filter device in which a medicinal liquid channel is formed connected to the extension tube. The air filter device includes: a housing having an air passage connecting a middle portion of the medicinal liquid channel to outside; a hydrophilic boundary filter disposed in the medicinal liquid channel and dividing the medicinal liquid channel into a first channel at an upstream side and a second channel at a downstream side; and a hydrophobic air-passing filter disposed at a boundary between the air passage and the first channel.

Advantageous Effects of Invention

According to an embodiment of the present disclosure, by conveniently filtering out air flowing inside together with a medicinal liquid or air produced from a medicinal liquid, it is possible to prevent air from being injected into a human body and prevent a medicine transfer pipe from being clogged with air.

According to an embodiment of the present disclosure, it is possible to considerably reduce the possibility of air being produced from a medicinal liquid at a downstream side of the air filter device.

According to an embodiment of the present disclosure, it is possible to filter out not only air, but also impurities in a medicinal liquid.

According to an embodiment of the present disclosure, it is possible to easily filter out air even if the air-passing filter is inclined in various directions and at various angles with respect to the direction of gravity.

According to an embodiment of the present disclosure, the possibility of leakage of a medicinal liquid is remarkably reduced, so particularly, when a medicinal liquid is a very dangerous medicine such as an anticancer medicine, it is possible to further improve safety.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram of the entire system of a medicinal liquid injection apparatus 1 according to an embodiment.

FIG. 2 is a perspective view of an air filter device 900 according to a first embodiment.

FIG. 3 is a perspective view showing the air filter device 900 of FIG. 2 viewed in another direction.

FIG. 4 is an exploded perspective view of the air filter device 900 of FIG. 2.

FIG. 5 is a vertical cross-sectional view of the air filter device 900 of FIG. 2.

FIG. 6 is a horizontal cross-sectional view of the air filter device 900 of FIG. 5 taken along line S1-S1′.

FIG. 7 is a horizontal cross-sectional view of the air filter device 900 of FIG. 5 taken along line S2-S2′.

FIG. 8 is a horizontal cross-sectional view of the air filter device 900 of FIG. 5 taken along line S3-S3′.

FIG. 9 is a perspective view showing the portion E1 of FIG. 4 in a predetermined direction.

FIG. 10 is a perspective view showing the portion shown in FIG. 9 viewed in another direction.

FIG. 11 is a perspective view showing the vent cap 912 of FIG. 4 viewed in another direction.

FIGS. 12A and 12B are views of a vent cap 912′ according to another embodiment, in which FIG. 12A is a vertical cross-sectional view and FIG. 12B is an elevation view.

FIGS. 13A and 13B are views of a vent cap 912″ according to another embodiment, in which FIG. 13A is a vertical cross-sectional view and FIG. 13B is an elevation view.

FIG. 14 is a vertical cross-sectional view of an air filter device 2900 according to a second embodiment.

FIG. 15 is a vertical cross-sectional view of the air filter device 2900 according to a modification of FIG. 14.

FIG. 16 is a vertical cross-sectional view of the air filter device 2900″ according to another modification of FIG. 14.

FIG. 17 is a perspective view of the air filter device 2900″ of FIG. 16.

FIG. 18 is an exploded perspective view of the air filter device 2900″ of FIG. 16.

MODE FOR THE INVENTION

Embodiments of the present disclosure are illustrated for the purpose of explaining the technical idea of the present disclosure. The scope of the rights according to the present disclosure is not limited to the embodiments presented below or the detailed descriptions of such embodiments.

All technical and scientific terms used in the present disclosure have the meaning generally understood by those of ordinary skill in the art to which the present disclosure pertains, unless otherwise defined. All terms used in the present disclosure are chosen for the purpose of more clearly describing the present disclosure and are not chosen to limit the scope of rights according to the present disclosure.

As used in the present disclosure, expressions such as “comprising”, “including”, “having”, and the like are to be understood as open-ended terms having the possibility of encompassing other embodiments, unless otherwise mentioned in the phrase or sentence containing such expressions.

The singular form described in the present disclosure may include a plural meaning, unless otherwise mentioned. This applies equally to the singular form recited in the claims.

The expressions, such as “first,” “second,” etc., which are shown in various embodiments of the present disclosure, are used to separate a plurality of elements from each other, and are not intended to limit an order or importance of the corresponding elements.

In the present disclosure, the description that one element is “connected,” or “coupled” to another element should be appreciated to indicate that one element may be directly connected, or coupled, to another element, and should be further understood that a new element may be interposed between one element and another element.

Terms “upstream” and “downstream” used herein are defined on the basis of the flow direction of a medicinal liquid when a pumping device 100 presses the medicinal liquid. In detail, the directions of the arrows F2 and F3 in FIG. 1 and F4 in FIG. 5 are defined as downstream directions and the direction opposite to the downstream direction is defined as an upstream direction.

It should be understood that the term “medicinal liquid” used herein includes not only liquid containing treatment substances, but liquid that assists treatment substances or can be used with treatment substances and liquid that can be injected into a patient. Priming liquid to be described below is a kind of those medicinal liquids.

Hereafter, embodiments of the present disclosure are described with reference to the accompanying drawings. The same or corresponding components may be given the same reference numerals in the accompanying drawings. Further, repeated description of the same or corresponding components may be omitted in the following description of the embodiments. However, omission of a description of components is not intended to mean exclusion of the components from the embodiments.

FIG. 1 is a conceptual diagram of the entire system of a medicinal liquid injection apparatus 1 according to an embodiment. Referring to FIG. 1, the medicinal liquid injection apparatus 1 may include an air filter device 2900 according to one embodiment and/or an air filter device 900 according to a different embodiment. The air filter device 2900 according to the one embodiment includes a medicine transfer pipe 820 that adjusts the flow rate of a medicinal liquid. The air filter device 900 according to the different embodiment does not include the medicine transfer pipe. The air filter device 900 and/or 2900 is connected to an extension tube 300, so a medicinal liquid can flow into the air filter device 900 and/or 2900 through the extension tube 300.

In this embodiment, a portion 330 of an additional extension tube 300 is connected to the downstream side of the air filter device 900, but in another embodiment that is not shown, a patient connector 600 or 600′ or an end cap 700 may be directly connected to the downstream end of the air filter device 900. In this embodiment, another air filter device 2900 is positioned at the downstream side of an air filter device 900, but in another embodiment that is not shown, a separate additional air filter device may not be provided at the downstream side of the air filter device 900.

Referring to FIG. 1, a process of injecting a medicinal liquid into a patient using the medicinal liquid injection apparatus 1 according to embodiments of the present disclosure includes a priming step and a medicinal liquid injection step that are sequentially performed.

In the priming step, a priming liquid is made to flow through an extension tube 300. The priming liquid flowing through the extension tube 300 flows into the air filter device 2900 according to an embodiment. The medicinal liquid injection apparatus 1 may include an end cap 700 separably connected to the downstream side of the air filter device 2900. The air in the extension tube 300 can be discharged outside through the air filter device 2900 and may be discharge outside through the end cap 700. The air in the extension tube 300 can be discharged outside through the air filter device 900 according to another embodiment.

Accordingly, the extension tube 300 and the air filter device 2900 are filled with the priming liquid. The priming liquid may be a liquid that contains treatment substances or that can be injected into a patient such as a saline solution.

The end cap 700 is configured to receive air and the priming liquid flowing through the air filter device 2900. The end cap 700 may be configured to allow air to flow outside, but to prevent the priming liquid from flowing outside.

The end cap 700 includes a vent filter 710 that blocks the priming liquid, but passes gas. The vent filter 710 includes a hydrophobic filter. The end cap 700 may include a sponge 720 disposed at an upstream side of the vent filter 710. The end cap 700 includes an end cap casing 730 accommodating the vent filter 710 therein. The end cap casing 730 accommodates the sponge 720 therein. The end cap casing 730 has a vent hole 730 a through which gas passes. The end cap 700 includes an end cap coupling portion 740 configured to be coupled to a downstream connecting portion 815 a of the air filter device 2900. The arrow E2 in FIG. 1 indicates the direction in which the end cap coupling portion 740 is coupled to and separated from the downstream connecting portion 815 a.

When the end cap 700 is filled with the priming liquid, it is possible to separate the end cap 700 from the air filter device 2900 and then connect a patient connector 600 or 600′ to the air filter device 2900.

The patient connector 600 or 600′ may include a needle 610 or a catheter. The patient connector 600 or 600′ includes a component that is injected into the body of a patient such as the needle 610.

The patient connector 600 or 600′ may include ‘an insert part including a component that is injected into the body of a patient such as the needle 610’ and ‘the other part’. The insert part and the other part may be configured to be separable from each other. In this case, with the insert part connected to a patient but separated from the other part, a user can couple the other part to the air filter device 2900 and then combine the insert part and the other part with each other. In this case, the liquid that has passed through the air filter device 2900 can flow into the body of the patient sequentially through the other part and the insert part.

The patient connector 600 or 600′ includes a needle supporting portion 620 that supports the needle 610. The patient connector 600 or 600′ includes a unit coupling portion 630 configured to be coupled to the downstream connecting portion 815 a of the air filter device 2900. The arrow E3 in FIG. 1 indicates the direction in which the unit coupling portion 630 is coupled to and decoupled from the downstream connecting portion 815 a.

For example, the patient connector 600 can be formed by sequentially connecting the needle 610, the needle supporting portion 620, and the unit coupling portion 630.

As another example, the patient connector 600 further has a patient connection tube fixing portion 650′ connected to the downstream side of the unit coupling portion 630. The patient connector 600′ further includes a patient connection tube 640′ connecting the patient connection tube fixing portion 650′ and the needle supporting portion 620. The patient connection tube 640′ may be made of a flexible material. The patient connector 600′ can be formed by sequentially connecting the needle 610, the needle supporting portion 620, the patient connection tube 640′, the patient connection tube fixing portion 650′, and the unit coupling portion 630.

In the medicinal liquid injection step, medicinal liquid is injected into the body of a patient by pressure that is applied by a pumping device 100. In the medicinal liquid injection step, the medicinal liquid is a liquid containing treatment substance. When the priming liquid is not a liquid containing treatment substance, but a saline solution, etc., the priming liquid can be injected first into the body of a patient and the liquid containing treatment substance flowing behind the priming liquid can be injected into the body of the patient.

The pumping device 100 includes a chamber 110 configured to be able to accommodate a medicinal liquid. The chamber 110 forms an internal space in cooperation with a pressing part 120. A medicinal liquid can be stored in the internal space. In another embodiment, a saline solution, etc. can be temporarily stored in the internal space. A discharge port 111 through which the liquid in the chamber 110 is discharged is formed at the chamber 110.

The pumping device 100 is configured to press a medicinal liquid. The pumping device 100 includes the pressing part 120 that presses the liquid in the chamber 110. The pressing part 120 can press the liquid in the chamber 110 by moving in a predetermined pressing direction Ap1. When a liquid is supplied into the chamber 110, the pressing part 120 is moved in the opposite direction Ap2 to the pressing direction Ap1. In FIG. 1, the position of the pressing part 120 that has moved in the opposite direction Ap2 is shown with reference to 120A.

The pumping device 100 may include a pressure operation part 130 that provides power such that the pressing part 120 moves in the pressing direction Ap1. For example, the pressure operation part 130 may be configured to press the liquid in the chamber 110 using volume expansion due to gas activation. As another example, the pressure operation part 130 provides a portion that a user can hold, so the user can move the pressing part 120 in the pressing direction Ap1 by applying force.

Though not shown, as another example, the pressing part 120 may be configured to press a liquid using the elasticity of an elastic member such as a balloon. In this case, the pressing part 120 may include the balloon configured to press a liquid in the balloon.

A medicinal liquid injection valve 200 is configured to fill the chamber 110 with a liquid. A liquid can flow into the extension tube 300 or the chamber 110 through the medicinal liquid injection valve 200. The medicinal liquid injection valve 200 may be connected to the extension tube 300 or, in another embodiment not shown in the figures, the medicinal liquid injection valve 200 may be connected to the chamber 110.

The medicinal liquid injection valve 200 has a first extension 210 connected to the downstream end of the first connecting portion 310 of the extension tube 300 and a second extension 220 connected to the upstream end of the second connecting portion 320 of the extension tube 300. The medicinal liquid injection valve 200 has an intake portion 230 configured such that a liquid can flow inside from the outside, and an intake port opening/closing part 240 that is separably coupled to the intake portion 230. The arrow E1 in FIG. 1 indicates the directions in which the intake port opening/closing part 240 is coupled and decoupled from the intake portion 230.

The extension tube 300 is configured to guide the flow of the priming liquid. The extension tube 300 can guide a medicinal liquid from the pumping device 100 to the air filter device 2900.

The extension tube 300 is configured such that a medicinal liquid discharged from the pumping device 100 by pressure applied by the pumping device 100 flows in the extension tube 300. The upstream end of the extension tube 300 is connected to the pumping device 100. The extension tube 300 has an upstream connecting portion 350 connected to a medicinal liquid injection discharge port 111 of the pumping device 100.

The downstream end of the extension tube 300 is connected to the air filter device 2900. A liquid that has passed through the extension tube 300 flows into the air filter device 2900 through an inlet of the air filter device 2900.

The extension tube 300 has a first connecting portion 310 connecting the upstream connecting portion 350 and the first extension 210 of the medicinal liquid injection valve 200. The extension tube 300 has a second connecting portion 320 connecting the second extension 220 of the medicinal liquid injection valve 200 and the air filter device 900 according to the different embodiment. The extension tube 300 has a third connecting portion 330 connecting the air filter device 900 and the downstream end of the extension tube 300.

The medicinal liquid injection apparatus 1 may include at least one connection tube opening/closing device 400. The connection tube opening/closing device 400 can block the flow of a liquid at a predetermined point of the extension tube 300 by pressing the outer side of the extension tube 300. The at least one connection tube opening/closing device 400 may include a first opening/closing device 410 that can change whether to open/close a point B1 of the first connecting portion 310 and a second opening/closing device 420 that can change whether to open/close a portion B2 of the second connecting portion 320. For example, the connection tube opening/closing device 400 may be configured to be in a clamp shape.

The priming step and the medicinal liquid injection step according to one embodiment are described hereafter. In the priming step according to the one embodiment, not a medicinal liquid, but a saline solution, etc. is used as the priming liquid. In the priming step according to the one embodiment, the intake port opening/closing part 240 is separated from the inlet 230, the first connecting portion 310 is closed by the first connection tube opening/closing device 410 (see B1), and the other portion of the extension tube 300 except for the first connecting portion 310 is opened. Referring to the arrows F1 and F3, the priming liquid such as a saline solution, etc. flows sequentially through the inlet 230, the second extension 220, the second connecting portion 320, the third connecting portion 330, and the air filter device 2900, whereby the extension tube 300 and the air filter device 2900 are filled with the priming liquid.

After the priming step according to the one embodiment, the medicinal liquid injection step according to the one embodiment is performed. In the medicinal liquid injection step according to the one embodiment, the intake port opening/closing part 240 is separated from the inlet 230, the second connecting portion 320 is closed by the second connection tube opening/closing device 420 (see B2), and the first connecting portion 310 is opened by separating the first connection tube opening/closing device 410 from the first connecting portion 310. Referring to the arrow F0, while a medicinal liquid flows into the chamber 110 through the medicinal liquid injection valve 200 and the first connecting portion 310, the pressing part 120 is moved in the direction Ap2. Thereafter, the intake port opening/closing part 240 is coupled to the inlet 230 and the second connection tube opening/closing device 420 is separated from the second connecting portion 320, thereby opening the extension tube 300. Referring to the arrows F2 and F3, thereafter, the pressing part 120 is moved in the pressing direction Ap1, so the medicinal liquid can sequentially pass through the extension tube 300 and the air filter device 2900.

A priming step and a medicinal liquid injection step according to a different embodiment are described hereafter. In the priming step according to the different embodiment, a medicinal liquid is used as the priming liquid. In the priming step according to the different embodiment, the chamber 110 is filled with a medicinal liquid, the end cap 700 is connected to the air filter device 2900, the inlet 230 is closed by the intake port opening/closing part 240, and the connection tube opening/closing device 400 is separated from the extension tube 300, thereby opening the extension tube 300. Referring to the arrows F2 and F3, thereafter, the pressing part 120 is moved in the pressing direction Ap1, so the medicinal liquid that is the priming medicinal liquid can sequentially pass through the extension tube 300 and the air filter device 2900. Accordingly, the extension tube 300 and the air filter device 2900 are filled with the priming liquid.

After the priming step according to the different embodiment, the medicinal liquid injection step according to the different embodiment is performed. In the medicinal liquid injection step according to the different embodiment, referring to the arrows F2 and F3, the pressing part 120 is further moved in the pressing direction Ap1, so the medicinal liquid can sequentially pass through the extension tube 300 and the air filter device 2900.

FIG. 2 is a perspective view of an air filter device 900 according to a first embodiment. FIG. 3 is a perspective view showing the air filter device 900 of FIG. 2 viewed in another direction. FIG. 4 is an exploded perspective view of the air filter device 900 of FIG. 2. FIG. 5 is a vertical cross-sectional view of the air filter device 900 of FIG. 2. The air filter device 900 according to the first embodiment is described hereafter with reference to FIGS. 2 to 5.

A medicinal liquid channel Q is formed in the air filter device 900. The air filter device 900 is connected to the extension tube 300. An air passage R diverging from the channel Q and connected to the outside is formed in the air filter device 900. A channel Q is formed in a housing 910. An air passage R is formed in the housing 910. The air passage R includes a vent hole 910 h formed at the housing 910.

The air filter device 900 includes a hydrophilic boundary filter 980 disposed in the medicinal liquid channel Q. The boundary filter 980 divides the channel Q into a first channel Q1 at the upstream side and a second channel Q2 at the downstream side. The boundary filter 980 is configured to act as a pressure interface between the first channel Q1 and the second channel Q2 when it is wetted with a medicinal liquid. The first channel Q1 and the second channel Q2 can have different pressures by the boundary filter 980. For example, the boundary filter 980 may be configured in any one manner of a net structure and a fiber structure. The boundary filter 980 may additionally have a function that filters out impurities.

The air filter device 900 includes a hydrophobic air-passing filter 960 disposed at the boundary between the air passage R and the medicinal liquid channel Q. The air-passing filter 960 is disposed at the boundary of the air passage R and the first channel Q1. The air-passing filter 960 blocks a medicinal liquid, but passes air. The arrow R1 in FIG. 5 indicates the direction in which air flows through the passage R.

Medicinal liquid inlet 910 a and outlet 910 b are formed at the housing 910. The medicinal liquid channel Q may be formed to connect the inlet 910 and the outlet 910 b. The air passage R is formed to connect the middle portion of the channel Q to the external space. The air passage R may extend in a first direction X from the middle portion of the channel Q. The term “first direction X” used herein may be defined as a direction that faces the air-passing filter 960 in the medicinal liquid channel Q.

The housing 910 includes a filter body 911 in which the boundary filter 980 is disposed. The filter body 911 includes a body part 911 d forming the outer surface. A contact channel Q1 c to be described below may be formed in the body part 911 d. A vent cap 912 may be coupled in the first direction X of the body part 911 d.

The filter body 911 includes an inlet portion 911 e where the inlet 910 a is formed. The inlet portion 911 e may protrude in the opposite direction to a second direction Y from the body part 911 d. The inlet 910 a may be formed at the end in the opposite direction to the second direction Y of the inlet portion 911 e. The term “second direction Y” used herein may be defined any one direction perpendicular to the first direction X.

The filter body 911 includes an outlet portion 911 c where the outlet 910 b is formed. The outlet portion 911 c may protrude in the second direction Y from the body part 911 d. The outlet 910 b may be formed at the end in the second direction Y of the outlet portion 911 c.

A coring groove 910 g that is recessed inward and in which the boundary filter 980 is disposed may be formed on the outer surface of the filter body 911. The groove 910 g is formed on an opposite side to the first direction X of the outer surface of the filter body 911. The groove 910 g may be formed by recessing the outer surface of the filter body 911 in the first direction X.

The housing 910 includes the vent cap 912 coupled to the filter body 911. The housing 910 has at least one vent hole 910 h formed at the position where the air passage R is connected to the external space. The vent hole 910 h is formed at the vent cap 912. The vent hole 910 h is a hole positioned at the position where the air passage R is connected to the outside. The vent hole 910 h may be open in the first direction X.

The vent cap 912 has a cover portion 912 a coupled to the housing 910. The cover portion 912 a may cover the air-passing filter 960. The cover portion 912 a covers the contact channel Q1 c. The cover portion 912 a may be formed in a plate shape having a thickness in the first direction X.

The vent cap 912 may include a vent protrusion 912 b protruding outward from the cover portion 912 a. The vent protrusion 912 b may protrude in the first direction X. The inner surface of the vent protrusion 912 b can define at least a portion of the air passage R. The vent hole 910 h may be formed at a protrusive end of the vent protrusion 912 b.

Air may exist in the chamber 110 and the extension tube 300. For example, in the priming step, air may remain without being completely removed in the chamber 110 and the extension tube 300. Air flowing in the air-passing filter 960 together with a medicinal liquid can be discharged through the first channel Q1 and the air passage R.

Further, air is dissolved in a medicinal liquid in the chamber 110 of the medicinal liquid injection apparatus 1. For example, an amount of the air that flows inside when the chamber 110 is filled with a medicinal liquid can be dissolved in the medicinal liquid in the chamber 110 under pressure larger than atmospheric pressure. In relation with this, the amount of air dissolved in the medicinal liquid can be inferred from a formula c1/p1=c2/p2 according to Henry's law. In the formula, c1 and c2 are molar concentration (mol/L) of the air dissolved in the medicinal liquid, and p1 and p2 are partial pressures of the air. c1 and p1 are values in an any one state, and c2 and p2 are values in another one state.

Since the first channel Q1 is connected with the air passage R, the first channel Q1 has internal pressure relatively low and close to the atmospheric pressure and the second channel Q2 may have internal pressure higher than that of the first channel Q1 due to downstream pipeline friction. Since the internal pressure p1 of the first channel Q1 is relatively low, the molar concentration c1 of the gas dissolved in the medicinal liquid in the first channel Q1 is relatively low, so air is easy to be produced from the medicinal liquid in the first channel Q1 and the produced air can be discharged outside through the passage R. Further, since the internal pressure of the second channel Q2 is relatively high, air is difficult to be produced from the medicinal liquid in the second channel Q2, so it is possible to reduce the possibility of air being produced from the medicinal liquid at the downstream side of the air-passing filter 960.

FIG. 6 is a horizontal cross-sectional view of the air filter device 900 of FIG. 5 taken along line S1-S1′. FIG. 7 is a horizontal cross-sectional view of the air filter device 900 of FIG. 5 taken along line S2-S2′. FIG. 8 is a horizontal cross-sectional view of the air filter device 900 of FIG. 5 taken along line S3-S3′. The air filter device 900 is described in detail with reference to FIGS. 5 to 8.

The first channel Q1 includes a contact channel Q1 c configured such that a medicinal liquid therein comes in contact with the air-passing filter 960. The first channel Q1 includes a facing channel Q1 b connected to the upstream side of the contact channel Q1 c. The facing channel Q1 b is configured to discharge a medicinal liquid into the contact channel Q1 c toward the air-passing filter 960 in the first direction X. The facing channel Q1 b may extend in the first direction X. The first channel Q1 may include an intake channel Q1 a connected to an inlet 910 a of the first channel Q1 and positioned at the upstream side of the contact channel Q1 c. The intake channel Q1 a may be connected to the upstream side of the facing channel Q1 b.

The second channel Q2 includes a discharge channel Q2 c connected to an outlet 910 b of the second channel Q2. The discharge channel Q2 c guides a medicinal liquid to be discharged through the outlet 910 b. The second channel Q2 includes an extension channel Q2 b including a portion extending in a direction opposite to the first direction X. The extension channel Q2 b curves or bends while extending. The extension channel Q2 b may be connected to the upstream side of the discharge channel Q2 c. The second channel Q2 may have a gap Q2 a between the boundary filter 980 and the housing 910. The extension channel Q2 b may be connected to the downstream side of the gap Q2 a.

In an embodiment, the intake channel Q1 a extends in the second direction. The facing channel Q1 b extends in the first direction X at the downstream side portion of the intake channel Q1 a. The facing channel Q1 b has an outlet 917 a being open in the first direction X. The facing channel Q1 b connects the intake channel Q1 a and the contact channel Q1 c to each other. In an embodiment, the contact channel Q1 c extends in the second direction Y. The contact channel Q1 c includes a space between the air-passing filter 960 and the boundary filter 980. The gap Q2 a of the second channel Q2 extends in the second direction Y. The gap Q2 a is positioned in a direction opposite to the first direction X of the contact channel Q1 c. The gap Q2 a is positioned in a direction opposite to the first direction X of the contact channel Q1 c with the boundary filter 980 therebetween. The extension channel Q2 b includes a portion curving or bending in the second direction from the direction opposite to the first direction X. The extension channel Q2 b has an inlet 917 b being open in the first direction X. The discharge channel Q2 c extends in the second direction.

The surface facing the first channel Q1 of the air-passing filter 960 may extend along a side of the first channel Q1. Although the air-passing filter 960 extends flat along a side of the first channel Q1, an air-passing filter 960 according to another embodiment not shown may extend while curving or bending along a side of the first channel Q1. Accordingly, the contact area and contact time between the air-passing filter 960 and the medicinal liquid in the channel Q can be increased, and various relevant examples about this configuration of the air-passing filter 960 and the channel Q are described.

The air-passing filter 960 may be configured to pass air in the first direction X. The air-passing filter 960 may extend in the second direction Y. The length in the second direction Y may be larger than the thickness in the first direction X of the air-passing filter 960. The contact channel Q1 c may be formed such that the length in the second direction Y is larger than the length in the first direction X facing the air-passing filter 960. The air-passing filter 960 may extend along the length of the contact channel Q1 c in the second direction Y.

The air-passing filter 960 may be formed in a plate shape with two sides. The air-passing filter 960 may extend in the second direction Y and a third direction Z. The term “third direction Z” used herein may be defined a direction perpendicular to the first direction X and the second direction Y. The length in the second direction Y and the length in the third direction Z may be larger than the thickness in the first direction X of the air-passing filter 960. The contact channel Q1 c may be formed such that the length in the third direction Z is larger than the length in the first direction X. The air-passing filter 960 may extend along the length of the contact channel Q1 c in the third direction Z.

A downstream side portion Q1 cb of the contact channel Q1 c may be spaced apart from an upstream side portion Q1 ca of the contact channel Q1 c in the second direction Y. The length in the second direction Y may be larger than the length in the third direction Z of the air-passing filter 960. The contact channel Q1 c may be formed such that the length in the second direction Y is larger than the length in the third direction Z.

The upstream side portion Q1 ca means a portion relatively close to the opening 917 a formed such that a medicinal liquid flows into the contact channel Q1 c and the downstream side portion Q1 cb means a portion relatively close to the opening 917 b formed such that a medicinal liquid is discharged from the contact channel Q1 c. In the embodiment, a medicinal liquid in the contact channel Q1 c passes through the boundary filter 980 in order to be discharged through the opening 917 b.

The air-passing filter 960 may cover the side of the first direction X of the contact channel Q1 c. The air-passing filter 960 may cover about 90% of the side of the first direction X of the contact channel Q1 c.

A cross-section perpendicular to the up-downstream direction of the contact channel Q1 c may be elongated to a side. The cross-section perpendicular to the up-downstream direction of the contact channel Q1 c may be formed such that the length in the third direction Z perpendicular to the first direction X is larger than the length in the first direction X.

The area of the air-passing filter 960 may be larger than the area of the boundary filter 980. The length in the first direction X of the air-passing filter 96 may be larger than the length in the first direction X of the boundary filter 980.

The boundary filter 980 may be configured to pass a medicinal liquid in the opposite direction to the first direction X. The boundary filter 980 may extend in the second direction Y. The length in the second direction Y may be larger than the thickness in the first direction X of the boundary filter 980. The boundary filter 980 may extend along the length of the contact channel Q1 c in the second direction Y.

The boundary filter 980 may be formed in a plate shape with two sides. The boundary filter 980 may extend in the second direction Y and a third direction Z. The length in the second direction Y and the length in the third direction Z may be larger than the thickness in the first direction X of the boundary filter 980. The boundary filter 980 may extend along the length of the contact channel Q1 c in the third direction Z. The length in the second direction Y may be larger than the length in the third direction Z of the boundary filter 980. The boundary filter 980 may cover a portion of the opposite side of the first direction X of the contact channel Q1 c.

The air filter device 900 may further include a hydrophobic secondary air-passing filter 970. The secondary air-passing filter 970 is disposed in the air passage R such that air that has passed through the air-passing filter 960 passes it. The secondary air-passing filter 970 can perform a function that prevents a medicinal liquid from flowing outside from the inside even if the air holes or the bonding portion of the air-passing filter 960 are damaged. The secondary air-passing filter 970 may be referred to as an additional hydrophobic air-passing filter 970.

The secondary air-passing filter 970 may be made of the same material as the air-passing filter 960 or may be formed by machining a porous plastic material. For example, the secondary air-passing filter 970 may be formed by machining hydrophobic porous plastic resin material in a shape corresponding to the secondary air-passing filter seat 914 on the air passage R. For example, a material of secondary air-passing filter 970 can be obtained from Porex Corporation (website: www.porex.com) at GA 30213, Fairburn of Georgia in U.S.A. A product named Porex Hydrophobic Vents by Porex Corporation can be used. This produce is made of a polyethyle polytetrafluoroethylene material.

Referring to FIGS. 5 and 6, the housing 910 may have a stopper protrusion 919 disposed in the intake channel Q1 a in which the extension tube 300 is inserted. The stopper protrusion 919 may catch an end of the extension tube 300. The stopper protrusion 919 protrudes toward the inside of the intake channel Q1 a from the inner surface of the housing 910 forming the boundary of the intake channel Q1 a. The stopper protrusion 919 limits the insertion depth of the extension tube 300 in the intake channel Q1 a of the air filter device 900. A catching surface formed on the stopper protrusion 919 to come in contact with the extension tube 919 is positioned in the opposite direction to the second direction Y further than the upstream end of the facing channel Q1 b. The catching surface of the stopper protrusion 919 is a surface opposite to the second direction Y of the stopper protrusion 919. A plurality of stopper protrusions 919 a and 919 b may be provided.

FIG. 9 is a perspective view showing the portion E1 of FIG. 4 in a predetermined direction. FIG. 10 is a perspective view showing the portion shown in FIG. 9 viewed in another direction. The air filter device 900 is described in detail with reference to FIGS. 6 to 10.

The housing 910 may have a facing protrusion 917 that protrudes in the first direction X to face the air-passing filter 960. The facing protrusion 917 may be positioned in the contact channel Q1 c. The outlet 917 a of the facing channel Q1 b may be formed at a protrusive end of the facing protrusion 917.

A first spacing distance in the first direction X between the protrusive end of the facing protrusion 917 and the air-passing filter 960 may be shorter than a second spacing distance in the first direction X between any other component in the contact channel Q1 c and the air-passing filter 960. For example, the first spacing distance is shorter than the spacing distance in the first direction X between the air-passing filter 960 and the boundary filter 980.

The housing 910 includes a boundary filter seat 915 to which the boundary filter 980 is coupled. The boundary filter seat 915 may extend along an edge of boundary filter 980. The boundary filter seat 915 may be formed on the filter body 911. The boundary filter seat 915 may protrude in the first direction X from the inner surface of the housing 910. The boundary filter 980 can be coupled to the boundary filter seat 915 in various ways such as UV (Ultraviolet) bonding, ultrasonic bonding, and forcible fitting.

The housing 910 may include a space-maintaining portion 916 protruding toward the boundary filter 980 in order to maintain the gap Q2 a between a surface opposite to the surface facing the first channel Q1 of the boundary filter 980 and the inner surface of the housing 910. The gap Q2 a constitutes a portion of the second channel Q2. The space-maintaining portion 916 can prevent deterioration of moisture permeation efficiency due to the boundary filter 980 sticking to the inner surface of the housing 810 when the boundary filter 980 is wetted with a liquid.

The space-maintaining portion 916 may be formed on the filter body 911. A protrusive end in the first direction X of the space-maintaining portion 916 may be positioned in the direction opposite to the first direction X further than the protrusive end in the first direction of the boundary filter seat 915. The space-maintaining portion 916 may protrude in the first direction X and extend in the second direction. The space-maintaining portion 916 may have at least one rib. A plurality of space-maintaining portions 916 a, 916 b, and 916 c may be arranged and spaced apart from each other in the third direction Z. A plurality of space-maintaining portions 916 a, 916 b, and 916 c may extend in parallel in the second direction Y.

FIG. 11 is a perspective view showing the vent cap 912 of FIG. 4 viewed in another direction. Referring to FIGS. 8 to 11, the filter body 911 includes a cap guide 911 f that guides the coupling position of the vent cap 912. The cap guide 911 f may protrude in the first direction X from the filter body 911. The cap guide 911 f may surround the circumference of the cover portion 912 a of the vent cap 912.

The filter body 911 may have a counter-cap coupling portion 911 g coupled to cap coupling portion 912 c of the vent cap 912. The counter-cap coupling portion 911 g may have a surface facing the first direction X.

The vent cap 912 may include the cap coupling portion 912 c extending along the edge of the cover portion 912 a. The cap coupling portion 912 c is formed on the side opposite to the first direction X of the vent cap 912. In the embodiment, the cap coupling portion 912 c is coupled to the counter-cap coupling portion 911 g in a fusion bonding manner according to ultrasonic bonding, but the vent cap 912 can be coupled to the filter body 911 in various ways such as UV (Ultraviolet) bonding and/or forcible fitting.

The housing 910 includes an air-passing filter seat 913 coupled to the air-passing filter 960. The air-passing filter seat 913 may protrude in the opposite direction to the first direction X. The air-passing filter seat 913 may extend along the edge of the air-passing filter 960. The air-passing filter seat 913 may be formed on the inner surface of the vent cap 912. The air-passing filter seat 913 may be positioned in the opposite side to the first direction X of the cover portion 912 a of the vent cap 912. In the embodiment, the air-passing filter 960 is coupled to the air-passing filter seat 913 by fusion bonding according to ultrasonic bonding, but the air-passing filter 960 may be coupled to the air-passing filter seat 913 in various ways such as UV (Ultraviolet) bonding and/or forcible fitting.

A gap 913 a may be formed between the side opposite to the side facing the first channel Q1 of the air-passing filter 960 and the inner surface of the housing 910. The air-passing filter seat 913 protrudes, thereby spacing the air-passing filter 960 from the inner surface of the vent cap 912. The gap 913 a constitutes a portion of the air passage R.

An air-passing filter seat 913 may protrude such that the rear surface of the air-passing filter 960 is spaced apart from the inner surface of the housing 910. The air-passing filter seat 913 may protrude toward the contact channel Q1 c from the inner surface of the housing 910 and may extend along the circumference of the air-passing filter 960.

The housing 910 may include a secondary air-passing filter seat 914 forming a groove 914 a in which the secondary air-passing filter 970 is inserted. The secondary air-passing filter seat 914 may be formed in the vent cap 912. The secondary air-passing filter seat 914 may be formed on the inner surface of the vent protrusion 912 b. In the embodiment, the secondary air-passing filter 970 is coupled to the secondary air-passing filter seat 914 by forcible fitting, but is not necessarily limited thereto. The secondary air-passing filter seat 914 may be referred to as an additional air-passing filter seat 914.

FIGS. 12A and 12B are views of a vent cap 912′ according to another embodiment, in which FIG. 12A is a vertical cross-sectional view and FIG. 12B is an elevation view. FIGS. 13A and 13B are views of a vent cap 912″ according to another embodiment, in which FIG. 13A is a vertical cross-sectional view and FIG. 13B is an elevation view. Referring to FIGS. 12A to 13B, at least one vent hole 910 h′ and 910 h″ may be elongated to a side or may have a plurality of vent holes 910 ha and 910 hb arranged to a side. Accordingly, even if the air filter device 900 is inclined in any direction, it is possible to more smoothly discharge air.

In another embodiment referring to FIGS. 12A and 12B, the vent hole 910 h′ is elongated in the second direction Y. An air passage R′ has a portion having a channel cross-sectional area that is long in the second direction Y. The vent hole 910 h′ may be elongated in the second direction Y between both ends of the vent cap 912. The vent protrusion 912 b′ may be elongated in the second direction Y to correspond to the vent hole 910 h′. A secondary air-passing filter (not shown) inserted in the vent protrusion 912 b′ may be elongated in the second direction Y to correspond to the vent protrusion 912 b′.

In another embodiment referring to FIGS. 13A and 13B, a plurality of vent holes 910 h″ are spaced from each other in the second direction Y. An air passage R″ includes a first passage Ra and a second passage Rb diverging from each other. The plurality of vent holes 910 h″ may be disposed at both ends of the vent cap 912 in the second direction Y. A plurality of vent protrusions 912 b″ corresponding to the plurality of vent holes 910 h″ may be provided. A plurality of vent protrusions 912 b 1 and 912 b 2 may be spaced apart from each other in the first direction X. A secondary air-passing filter (not shown) may be disposed in each of the plurality of vent protrusions 912 b 1 and 912 b 2. A plurality of secondary air-passing filters (not shown) corresponding to the plurality of vent protrusions 912 b 1 and 912 b 2 may be provided.

FIG. 14 is a vertical cross-sectional view of an air filter device 2900 according to a second embodiment. The air filter device 2900 is described hereafter mainly in relation to differences from the first embodiment with reference to FIG. 14.

The boundary filter 980′ may be implemented in various shapes and various arrangement manners. The boundary filter 980′ may be disposed to have a thickness in a direction Y facing the inlet of the capillary channel 820 p. Various shapes and boundaries of a first channel Q1′ and a second channel Q2′ may be implemented. The second channel Q2′ includes the discharge channel Q1 c described above and may not include the extension channel Q2 b and the gap Q2 a. The first channel Q1′ may have a contact channel Q1 c having various shapes. The position and the arrangement direction of the boundary filters 980 and 980′ shown in FIGS. 5 and 14 are only some examples and are not necessarily limited thereto.

The air filter device 2900 further includes an integrated medicine transfer pipe device. In the embodiment, the medicine transfer pipe 820 is disposed at the downstream side of the boundary filter 980′, so it is possible to adjust the flow rate of the medicinal liquid in the channel Q.

The medicine transfer pipes 820 may have a function of a flow restricting component. That is, the medicine transfer pipes 820 may have a function of restricting the flow rate of a medicinal liquid flowing through the channel Q. For example, the medicine transfer pipes 820 may include a capillary pipe. As another example, the medicine transfer pipes 820 may include a polymeric microtube. Further, the medicine transfer pipes 820 may be made of various materials in various shapes having a capillary channel.

The air filter device 2900 includes the medical transfer pipe 820 having a capillary channel 820 p connected with the channel Q. For example, the capillary channel 820 p has a diameter of about 0.04 to 0.08 mm, thereby restricting the flow rate of a medicinal liquid.

At least a portion of the medical transfer pipe 820 may be in contact with the inner surface of the housing 910. The medical transfer pipe 820 may be disposed through the sealing member 830. An upstream end of the medical transfer pipe 820 is the inlet of the capillary channel 820 p. The upstream end of the medical transfer pipe 820 may be in contact with the spacer 840.

The medicinal liquid channel Q is connected with the capillary channel 820 p. The channel Q, the capillary channel 820 p, and the downstream channel P2 may be sequentially positioned in the entire channel of the air filter device 2900. The channel Q and the downstream channel P2 may have a channel cross-sectional area larger than that of the capillary channel 820 p.

The channel Q can connect the inlet 910 a to the capillary channel 820 p. An intake filter 850 to be described below may be disposed in the channel Q. A hole of the spacer 840 to be described below may form a downstream end portion of the channel Q.

A downstream channel P2 disposed at a downstream side of the capillary channel 820 p may be formed in the air filter device 2900. A discharge port O2 of the air filter device 2900 is the exit of the downstream channel P2.

In this embodiment, a downstream space 820 t is formed between the capillary channel 820 p and the downstream channel P2 in the channel Q. The downstream space 820 t has a channel cross-sectional area larger than a channel cross-sectional area of the second capillary channel 820 p 2. The downstream space 820 t has a channel cross-sectional area larger than a channel cross-sectional area of the downstream channel P2.

The medicinal liquid transfer pipe 820 is coupled to the housing 910. The housing 910 may include a medicinal liquid transfer pipe housing 811 to which the medicinal liquid transfer pipe 820 is coupled. The medicinal liquid transfer pipe housing 811 may be coupled to the filter body 911. The housing 910 may include a downstream housing 815 coupled to the downstream side portion of the medicine transfer pipe housing 811.

The air filter device 2900 may include at least one sealing member 830 fitted between the outer surface of the medicine transfer pipe 820 and the inner surface of the housing 910. The sealing member 830 can prevent a medicinal liquid from flowing between the outer surface of the medicine transfer pipe 820 and the inner surface of the housing 910. The sealing member 830 can surround the medicine transfer pipe 820. The sealing member 830 may be formed in a ring shape. The sealing member 830 may be made of an elastic material such as rubber.

The air filter device 2900 includes the spacer 840 being in contact with the upstream end of the medicine transfer pipe 820. A hole is formed through the center of the spacer 840. A medicinal liquid that has passed through the hole of the spacer 840 flows into the capillary channel 820 p.

The spacer 840 may be disposed between the upstream end of the medicine transfer pipe 820 and the intake filter 850, thereby maintaining a gap. The spacer 840 spaces the intake filter 850 from the inlet of the capillary channel 820 p such that the intake filter 850 does not block the inlet of the capillary channel 820 p.

The air filter pipe device 2900 may include an intake filter 850 disposed at the upstream side of the capillary channel 820 p. The intake filter 850 may be disposed at the downstream side of the air-passing filter 960. The intake filter 850 may be disposed at the downstream side of the boundary filter 980. The intake filter 850 is disposed such that a medicinal liquid flowing in the channel Q passes through the intake filter 850. The intake filter 850 can prevent relatively large air bubbles (bubbles) that have passed through the channel Q from clogging the inlet of the capillary channel 820 p.

FIG. 15 is a vertical cross-sectional view of the air filter device 2900′ according to a modification of FIG. 14. Referring to FIG. 15, the air filter device 2900′ includes a plurality of medical transfer pipe 820 each having a capillary channel 820 p connected with the channel Q. In this embodiment, the air filter device 2900′ includes only two medicine transfer pipes 821 and 822, but is not limited thereto and may include three or more medicine transfer pipes. The air filter device 2900′ includes a housing 910 to which the medicine transfer pipes 820 are coupled.

The medicine transfer pipes 820 include a first medicine transfer pipe 821 having a first capillary channel 820 p 1 constituting a portion of the channel Q and a second medicine transfer pipe 822 having a second capillary channel 820 p 2 constituting a portion of the channel Q. The second capillary channel 820 p 2 is disposed downstream than the first capillary channel 820 p 1 such that a medicinal liquid that has passed through the first capillary channel 820 p 1 flows therein.

An intervention space 820 s is formed between two medicine transfer pipes 821 and 822 adjacent to each other in the up-downstream direction in an air filter device 2900′. A channel cross-sectional area of the intervention space 820 s is larger than a channel cross-sectional area of the first capillary channel 820 p 1 and a channel cross-sectional area of the second capillary channel 820 p 2. The term “channel cross-sectional area” used in the present disclosure means a cross-sectional area of a channel cut perpendicularly to the up-downstream direction.

The intervention space 820 s is formed between the first medicine transfer pipe 821 and the second medicine transfer pipe 822 in the housing 910. The intervention space 820 s is configured such that a medicinal liquid that has passed through the first capillary channel 820 p 1 flows therein. The intervention space 820 s is configured such that the medicinal liquid therein moves to the second capillary channel 820 p 2.

The inner surface of the housing 910 may form at least a portion of the boundary of the intervention space 820 s. The first medicine transfer pipe 821 may form a portion of the boundary of the intervention space 820 s. The second medicine transfer pipe 822 may form a portion of the boundary of the intervention space 820 s.

The first medicine transfer pipe 821 and the second medicine transfer pipe 822 are coupled to the housing 910. The channel Q, the first capillary channel 820 p 1, the intervention space 820 s, and the second capillary channel 820 p 2 may be sequentially positioned on the entire channel of the air filter device 2900.

The at least one sealing member 830 includes a first sealing member 831 fitted between the outer surface of the first medicine transfer pipe 821 and the inner surface of the housing 910. The at least one sealing member 830 includes a second sealing member 832 fitted between the outer surface of the second medicine transfer pipe 822 and the inner surface of the housing 910. The spacer 840 may be in contact with the upstream end of the first medicine transfer pipe 821.

FIG. 16 is a vertical cross-sectional view of the air filter device 2900″ according to another modification of FIG. 14. FIG. 17 is a perspective view of the air filter device 2900″ of FIG. 16. FIG. 18 is an exploded perspective view of the air filter device 2900″ of FIG. 16.

Referring to FIGS. 16 and 18, the air filter device 2900″ may further have an air vent 890 configured to connect the intervention space 820 s to the external space such that air in the intervention space 820 s and air in a medicinal liquid are discharged to the external space. A vent hole 890 h of the air vent 980 may be formed in the medicine transfer pipe housing 811.

The air vent 890 includes a hydrophobic air-passing filter 891. The air vent 890 has an air channel (not shown) through which the air in the intervention space 820 s passes (see the arrow R2). The air-passing filter 891 forms the boundary between the air passage of the air vent 890 and the intervention space 820 s.

The intervention space 820 s may further include an air passage connection space 820 sp configured to be connected with the air passage of the air vent 890. The air passage connection space 820 sp may be formed at a radial end of the intervention space 820 s. The air-passing filter 891 forms the boundary between the air passage of the air vent 890 and the air passage connection space 820 sp.

The rear surface of the air-passing filter 960′ of the air filter device 2900″ is in close contact with the inner surface 913′ of the housing 910, so an air passage R can be formed without the gap 913 a described above.

The medicine transfer pipe housing 811 may include a first coupling portion 811 a coupled to the filter body 911. The first coupling portion 811 a may have a hook shape. The first coupling portion 811 a may be latched to a first counter-coupling portion 911 a of the filter body 911.

The medicine transfer pipe housing 811 may include a second coupling portion 811 b coupled to the downstream housing 815. The second coupling portion 811 b may have a hook shape. The second coupling portion 811 b may be latched to a second counter-coupling portion 815 b of the downstream housing 815.

The medicine transfer pipe housing 811 may have a first seat 811 c in which a portion of the downstream side of the filter body 911 is inserted. The medicine transfer pipe housing 811 may have a second seat 811 d in which a portion of the upstream side of the downstream housing 815 is inserted.

The medicine transfer pipe housing 811 may have a fitting portion 811 e disposed between the first seat 811 c and the second seat 811 d. The intervention space 820 s is positioned in the fitting portion 811 e. The downstream end of the first medicine transfer pipe 821 is inserted in the fitting portion 811 e. The upstream end of the second medicine transfer pipe 822 is inserted in the fitting portion 811 e.

The filter body 911 may accommodate at least a portion of the first medicine transfer pipe 821. The upstream side portion of the first medicine transfer pipe 821 is accommodated in the filter body 911. An outlet portion 911 c′ of the filter body 911 is inserted in the medicinal liquid transfer pipe housing 811.

The downstream housing 815 may accommodate at least a portion of the second medicine transfer pipe 822. The downstream side portion of the second medicine transfer pipe 822 is accommodated in the downstream housing 815. The downstream housing 815 has an insertion portion 815 c that is inserted in the medicine transfer pipe housing 811. The discharge port O2 is formed at the downstream housing 815. The downstream connecting portion 815 a connected with the patient connector is formed at the downstream housing 815.

Although the spirit of the present disclosure has been described with reference to the embodiments and the examples shown in the figures, it should be understood that the present disclosure can be replaced, changed, and modified by those skilled in the art in various ways without departing from the spirit and scope of the present disclosure. Further, those replacements, changes, and modifications should be considered as being included in the claims. 

1. An air filter device for medicinal liquid injection in which a medicinal liquid channel is formed, the air filter device comprising: a housing having an air passage that diverges from the medicinal liquid channel and is connected to outside; a hydrophilic boundary filter disposed in the medicinal liquid channel and dividing the medicinal liquid channel into a first channel at an upstream side and a second channel at a downstream side; and a hydrophobic air-passing filter disposed at a boundary between the air passage and the first channel.
 2. The air filter device of claim 1, wherein a surface of the air-passing filter facing the first channel extends along a side of the first channel.
 3. The air filter device of claim 1, wherein the first channel includes a contact channel configured such that a medicinal liquid in the contact channel comes in contact with the air-passing filter, and the contact channel is formed such that a length of the contact channel in a first direction facing the air-passing filter is shorter than a length of the contact channel in a second direction that is any one direction perpendicular to the first direction.
 4. The air filter device of claim 3, wherein the air-passing filter is configured to pass air in the first direction and extends in the second direction.
 5. The air filter device of claim 3, wherein the contact channel is formed such that a length of the contact channel in a third direction perpendicular to the first direction and the second direction is larger than a length of the contact channel in the first direction.
 6. The air filter device of claim 5, wherein the air-passing filter is configured to pass air in the first direction and extends in the second direction and the third direction.
 7. The air filter device of claim 5, wherein a downstream side portion of the contact channel is spaced apart from an upstream side portion of the contact channel in the second direction, and the contact channel is formed such that the length of the contact channel in the second direction is larger than the length of the contact channel in the third direction.
 8. The air filter device of claim 1, wherein the first channel includes a contact channel configured such that a medicinal liquid in the contact channel comes in contact with the air-passing filter, and a cross-section of the contact channel is formed such that a length of the cross-section in a first direction facing the air-passing filter is shorter than a length of the cross-section in a second direction perpendicular to the first direction.
 9. The air filter device of claim 1, wherein the first channel includes: a contact channel configured such that a medicinal liquid in the contact channel comes in contact with the air-passing filter; and a facing channel connected to an upstream side of the contact channel and configured to discharge the medicinal liquid into the contact channel in a first direction facing the air-passing filter.
 10. The air filter device of claim 9, wherein the housing includes a facing protrusion protruding in the first direction to face the air-passing filter and having an outlet of the facing channel formed at a protrusive end of the facing protrusion.
 11. The air filter device of claim 9, wherein the facing channel extends in the first direction.
 12. The air filter device of claim 1, wherein the housing includes an air-passing filter seat extending along an edge of the air-passing filter and coupled to the air-passing filter.
 13. The air filter device of claim 12, wherein a gap is formed between one side of the air-passing filter that is opposite to the other side of the air-passing filter facing the first channel, and an inner surface of the housing, and the gap constitutes a portion of the air passage.
 14. The air filter device of claim 1, further comprising an additional hydrophobic air-passing filter disposed in the air passage and configured to pass air that has passed through the air-passing filter.
 15. The air filter device of claim 14, wherein the housing includes an additional air-passing filter seat having a groove in which the additional hydrophobic air-passing filter is inserted.
 16. The air filter device of claim 1, wherein the housing includes: a filter body in which the boundary filter is disposed; and a vent cap having a vent hole constituting at least a portion of the air passage, and coupled to the filter body.
 17. The air filter device of claim 1, wherein the housing includes a gap-maintaining portion protruding in a direction facing the boundary filter to maintain a gap formed between one side of the boundary filter, the one side being opposite to the other side of the boundary filter facing the first channel, and an inner surface of the housing, and the gap constitutes a portion of the second channel.
 18. The air filter device of claim 17, wherein the second channel includes an extension channel connected to a downstream side of the gap and having a curved or bent portion.
 19. The air filter device of claim 1, wherein the housing has at least one vent hole positioned at a position where the air passage is connected to an external space, and the at least one vent hole includes a plurality of vent holes arranged along a specified direction, or is elongated along the specified direction.
 20. A medicinal liquid injection apparatus comprising: a pumping device configured to press a medicinal liquid; an extension tube in which the medicinal liquid flowing out of the pumping device by pressure applied by the pumping device flows; and an air filter device in which a medicinal liquid channel is formed connected to the extension tube, wherein the air filter device includes: a housing having an air passage connecting a middle portion of the medicinal liquid channel to outside; a hydrophilic boundary filter disposed in the medicinal liquid channel and dividing the medicinal liquid channel into a first channel at an upstream side and a second channel at a downstream side; and a hydrophobic air-passing filter disposed at a boundary between the air passage and the first channel. 